How to restrict mining to a certain nodes in ethereum private network

Question

I have created a private network of ethereum block chain. The network is open for anybody to join and run their own node.

But I dont want them to mine blocks. I Want to restrict mining to certain nodes.

Any lead is appreciated.

Answer 1

There are Proof of Authority (PoA) consensus algorithms for parity and geth. With PoA you can explicitly specify who is allowed to mine/seal blocks.

For a step-by-step guide for geth's clique PoA, see https://hackernoon.com/setup-your-own-private-proof-of-authority-ethereum-network-with-geth-9a0a3750cda8